Leak detector



16e-250 SF2 Fwfo XR agmowl? M. M. KINLEY LEAK DETECTOR Filed Nov. l,1957 Swanton M M. ,if/NLE V Patented Aug. 6, 1940 UNTED STATES FATNTFFHCE 3 Claims.

byisourid caused biiquidieakirig through a weill s'*m'l"belfleted andvariations in the ii'tehsity'bf'the sound determined as anmindicationpoLtheilocationloLlks "nother object is to provide methodn gfwlgcatingleaks by deterleleieael 'treinoinrs ih hg'im'dially.ithecasingfthiite yof sound pro gillliidnhY..leakage,throughltlicasfiigfM "Still anotherobject is to locate leaks by moving a sound sensitive unit within thecasing to render observable the iiuctuationoi sound along the casing.

Still' another object is to provide a leak de tecting system fordetermining the location of the leakage of water into a casing cementedin a well bore.

The various objects and features of the invention will be understoodfrom the following detailed description of a typical manner of carryingout the method and a typical form of the invention throughout whichdescription reference' is made to the drawing in whichz.

Fig. 1 is a vertical section through awell bore and illustrating anembodiment of the invention.

Fig. 2 illustrates graphical .results to be obtained in accordance withthe invention.

Considerable dimculty is encountered by the existence of leaks throughcasing anchored withm a well bore. Such leaks may permit liquid to flowoutwardly from within the casing, or, more frequently, they permit freshor salt water to leak into the well and hence to undesirably dilutefluid produced from the well.

By means or' the present invention such leaks may be readily anddeiinitely located by determining the location of maximum sound producedby the liquid passing through the openings in the casing whereupon stepsmay be taken to close the leaks or to seal off -a portion of the casingwherein such leak or leaks occur.

In Fig. 1 is shown a well bore l, within which is positioned a casing 2,anchored in place by means of cement 3 whereby liquid is not permittedto enter the annular space 4 between the bore l and the casing 2. At 5is shown a water bearing stratum through which water may flow into theannular space 4 and rise to a normal level lll, which is determined bythe liquid head which causes water to ow through the stratum 5. Leaksare shown in the casing 2 at Il and i2, whereby liquid may enter thecasing.

As the invention comprehends the detection of sound produced by liquidpassing through the leaks in the casing 2 a sound detector l5 isprovided, such detector being suspended from a cable I6, which passesover a sheave in thederrick 2l and iswound upon a drum 22, driven fromany suitable source of power (not shown). This arrangement'permits thedetector l5 to be lowered into and withdrawn from the bore hole.

The sound detector I5 comprises an enclosed chamber for housing a.suitable sound detecting mechanism, such, for example, as a microphonewhich responds to vibrations of the sound produced byjthe leaking liquidand renders such sound observable at the mouth of the well bore.

The detector unit l5 is provided with arms or bumpers 25, preferably ofrubber, which are adapted to contact the casing when the detector moveseccentrically within the casing 2. This construction avoids theintroduction of extraneous sounds which would be produced by contact ofthe detector unit with the casing 2.

It is to be understood that while a microphone has been specicallyreferred to, the invention is not limited thereto for it is apparentthat other suitable sound detecting mechanisms may be utilized.

When a microphone is used, as is illustrated in Fig. 1, the cable i6will include suitable conductors to complete a circuit from the detectorunit l5 to the earths surface. Such conductors are shown as ending interminals 30 or 3l at the drum 22 and a circuit is completed from theseterminals through wires 32 to a suitable indicating device, generallydesignated as 33. The indicating device 33 is so constructed as toprovide visual'or aurai indications of the intensity of the sound at thedetector unit l5 as such unit is lowered into or withdrawn from thecasing 2. As the specific construction of the indicating device 33 formsno part of the prent invention and as such devices are well known in theart, conventional illustration only is shown of this device.

A preferred indication is a graphical record which may be produced as bymeans of a. moving stylus or photographically in a manner well known inthe art. Such a graph is shown at 3E in Fig. 2 in which the ordinaterepresents sound intensity while the abscissa indicates depth ordistance from the mouth of the bore hole to the detector unit l5. Theinflection S in the graph 35 occurs as the detector l5 approaches leak li. After'the leak is passed the sound intensity decreases but againincreases at 31 as the leak l2 is approached.

It is believed apparent that the graph- 35 forms a. permanent recordwhich enables definite location of the leaks l I and l2 whereby thenecessary steps may be taken to close such leaks and to eliminate thedilculties encountered thereby.

In practice of the invention it is obvious that there must be adiierential head between the interior and exterior of the casing 2.Unless a static condition has been reached due to the leakage throughthe casing such diierential head exists and observations may be made bytraversing the casing 2 with the detector unit l5. II, however, staticconditions have been reached a desirable diierential head may be createdby adding liquid to the interior of the casing or by withdrawing liquidtherefrom. As this latter procedure is preferable the desireddiierential head may be produced by withdrawing liquid until the surfaceof the liquid in the casing reaches a suitable level such as thatindicated at ll so that such head determined by the difference inelevation of the levels IB and il will be instrumental in causing liquidto iow through existing leaks to the interiorof the casing. Sbservationsmay be made throughout the interval of time necessary for the liquid torise from the level I'l`to the normal static level IB.

. It is to be understood that observations may be made continuously asthe detector unit i5 is lowered within the casing 2 whereby a continuousindication is given by the instrument 33. Such observations, if regardedas above described, give rise to a continuous graph as illustrated inFig. 2. On the .other hand, it is apparent that observations 'may bemade intermittently, if de sired, without departure from the spirit orthe invention.

It is obvious that the-construction shown and the procedure described iscapable of modification and such modifications as fall within the scopeof the appended claims is considered to be within the spirit and intentof the invention.

What is claimed as new is:

l. The method of determining the location of leaks in the casing withina. bore hole comprising the steps of altering the normal static liquidlevel within the casing to produce a hydrostatic head between theinterior and exterior of the casing, picking up the sound from theliquid flow caused by the leakage due to such hydrostatic head, andmeasuring the intensity of the sound as an indication of the location ofleaks in the casing.

2. The method of determining the location of leaks in the casing Withina bore hole comprising the steps of lowering the liquid level within thecasing to produce a hydrostatic head between the interior and' exteriorof the casing, picking up the sound of leakage caused by suchhydrostatic head and measuring, the intensity of the sound as anindication of the location of leaks in the casing.

3. The method of determining the location of leaks in the casing withina. bore hole comprising the steps of altering the normal static liquidlevel within the casing to produce a hydrostatic head between theinterior and exterior of the casing so that leakage dueto said head willset up sound vibrations in the liquid inlthe casing, moving a sounddetector longitudinally of the casing, and determining the varyingamplitude of the sound as an indication of the location of leaks in thecasing.

MYRON M. MNLEY.

